Up until recently, when watching TV, I'd use either the DPL2 or Logic7 settings on my h/k AVR 520 receiver. Now I prefer to listen to TV in plain old 2-channel stereo. I get a much better soundstage and everything sounds more "real", if you can dig that.
I think part of this is the fact that both DPL2 and Logic7 collapse a lot of the sound to the center channel speaker, in my case a VP100, and IMO it's not up to the task. For DD and dts material though, the VP100 is adequate since most of what it's handling is dialogue. Some receivers have the option of "tuning" DPL2's settings, letting you spread the sound out more, unfortunately mine doesn't. Don't get me wrong, the VP100 is a decent speaker, it just NO match for my M40's.
Anyway, if you're happy with the sound from your set-up without a center channel, don't get one. If it ain't broke don't fix it.
Good luck.
